// Copyright 2011 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package org.apache.tapestry5.csrfprotection.victimapp.services;

import java.security.SecureRandom;
import java.util.Hashtable;

/**
 * Provides the CSRF token. 
 * Implemented strategies:
 * -) per session token
 */
public class CsrfServiceImpl implements CsrfService{
	// current token for a http session
	private final Hashtable<String, String> sessionToken = new Hashtable<String,String>();  
	
	// token generator
	private final SecureRandom secureRandom = new SecureRandom();	

	public String getToken(String sessionID) {
		if(sessionID == null)
			return null;
	
		if(sessionToken.containsKey(sessionID)){
			return sessionToken.get(sessionID); 
		}
		return createToken(sessionID);		
	}
	
	private synchronized String createToken(String sessionID){
		String token =  Long.toString(secureRandom.nextLong());
		sessionToken.put(sessionID,token);
		return token;		
	}
}
